Basic Android

Android Basics

• Install 32 or 64 bit Java JDK http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html

• App Inventor Pretty basic web interface an blocks editor to build simple android apps http://appinventor.mit.edu/about/
  • Setup App Inventor http://appinventor.mit.edu/

• Android SDK
  • http://developer.android.com/sdk/index.html
  • Download Android Studio
  • For SDK path we will use c:\user\Android

• Android NDK
  • we're not covering this http://developer.android.com/sdk/ndk/index.html

Basics

• src folder containing all the source
• res folder containing all the resources

folder hierarchy explained http://developer.android.com/tools/projects/index.html

First app demo http://developer.android.com/training/basics/firstapp/running-app.html

App lifecycle http://developer.android.com/guide/components/activities.html

Resources

No DPI or PPI Andoid uses dp density independent pixels or sp scale interdependent pixels http://developer.android.com/guide/topics/resources/more-resources.html#Dimension

also see supporting multiple screens http://developer.android.com/guide/practices/screens_support.html

Activities

Activity life cycle http://developer.android.com/guide/topics/fundamentals/activities.html#Lifecycle

Get an instance of an object from the R class

/** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        //Get the Button and the TextView from the Resource class
        Button btn = (Button)this.findViewById(R.id.button1);
        final TextView tv = (TextView)this.findViewById(R.id.textView1);  
        String s = "hello";
        tv.setText(s);
    }

notice the cast to the type also notice that the TextView is marked as final 
this is so that we can use it in an inner method

handle a click event

btn.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				tv.setText(d.About());
			}
		});

Events

Lots more good reading http://developer.android.com/guide/topics/fundamentals.html

Dog Class in java

<syntaxhighlight lang="java"> public class Dog {

public String Name; public int Weight; public String BarkSound;

//Constructor public Dog() { this.Name = "fido"; this.Weight = 1; this.BarkSound = "woof"; }

public void Eat() { this.Weight++; } public void Poop() { this.Weight--; }

public String About() { return String.format("Hello my name is %s. I weigh %s lbs", this.Name, this.Weight); }

} </syntaxhighlight lang="java">>

In Class Demo

• Get and install Android Studio this demo uses .086 https://developer.android.com/sdk/installing/studio.html
• Start Android Studio
• Select ConfigureTemplate:AndroidStudioConfigure.png
• Select Android SDK ManagerTemplate:AndroidStudioSDKManager.png
• Make sure you have a current SDK for this Demo we will use 23.05 Template:AndroidSDKManagerCurrentVersion.PNG
• Go back to the main menu and select New ProjectTemplate:AndroidStudioNewProject.PNG
• Name the Project OOPDog and select NextTemplate:AnroidStudioConfigureNewProject.PNG
• Select a Minimum SDK for this demo we will use ASI15 : IceCreamSandwichTemplate:AnroidStudioConfigureNewProjectSDK.PNG
• Select Blank Activity for the Project templateTemplate:AndroidStudioBlankActivity.PNG
• The defaults are fine for the activity name select nextTemplate:AnroidStudioNewProjectAcvtivity.PNG

• After a minute or so you can open the Project window if it isn't already open Att-1 or View/Tool Windows/Project Template:AndroidStudioShowOpenMyActivity.png
• Add Dog class Template:AndroidStudioNewClass.png
• Name the class Dog Template:AndroidStudioNewClassName.PNG

• Here is the c# dog class we have been using we need to change it a bit Android Studio CSharpDog Code

• In Java Android Studio JavaDog